METHOD AND DEVICE FOR SPLICING MULTIFILE TEXTILE FIBERS

Description

[0001] The present invention relates to methods for the continuous manufacture of elongated composite materials produced by impregnating multifilament textile fibers with a hardenable composition and it relates more particularly to a method for splicing such textile fibers before their impregnation.

[0002] Document EP 1 174 250 describes a method and an installation for the continuous impregnation of very long fibers with resin for the manufacture of very long elongated composite elements, composites which comprise reinforcing fibers embedded in a hardened resin matrix. The method described comprises a step of driving a bundle of reinforcing fibers, from a fiber storage reel, to pass it into a vacuum enclosure and then into an impregnation chamber where the fibers are impregnated with resin, followed by a step during which the impregnated fibers pass through a calibration die after having previously stabilized the shape of the impregnated material by at least partial polymerization of the resin of the impregnated material. Calibration dies of predetermined shape and dimensions are also present at the inlet of the vacuum enclosure and before the impregnation chamber.The system's dies are all finely sized according to the diameter of the reinforcing fiber bundle. The system includes a traction roller that drives the fibers from the fiber storage reel and a receiving reel for the impregnated material.

[0003] Although operating satisfactorily, it turned out that replacing an emptied storage reel with a new reel required a complete shutdown of the installation and a thorough cleaning of the installation before restarting with the new reel in place, which involves significant downtime with negative consequences on productivity. Indeed, after an operating period of approximately five hours, the fiber storage reel is emptied. The installation is then stopped and the empty reel is replaced with a new full reel. The impregnation chamber must then be completely emptied and the installation cleaned before restarting the installation. This shutdown period can take between one and three hours.There is therefore an increased need to be able to join the end of the fibers of one reel end to the beginning of those of a new reel and to bring them together in a single piece, without completely stopping the installation.

[0004] Various solutions are known in the state of the art for splicing textile fibers. Such a solution is described in document JP5-239729. According to this document, the end portions of two bundles of glass fibers are first inserted into a circular cross-section passage of a splicing device. Compressed air is blown through an air inlet perpendicular to this passage so as to open the end portions of the bundles of glass fibers and to mix the bundles of glass fibers together. This produces a combined bundle of glass fibers. However, it should be noted that at the junction of the two bundles, the thickness of the combined bundle is greatly increased.However, such a solution is not suitable for use in a continuous manufacturing installation for elongated composite materials of the type described above because the thick joining part cannot pass through the calibration dies of the installation.

[0005] Another solution has been described in document US 2019 / 0135576 which teaches the use of a flat support table for an end portion of a first bundle of fibers and on which a roller transfer device places the end portion of a second bundle. The end portion of the second bundle is first hooked, then wound around the roller of the transfer device. This roller is then positioned near the support table and unwinds the end portion of the second bundle by superimposing it on that of the first bundle. A thermocompression device is then applied to the superimposed end portions of the two bundles which are thus welded to form a single bundle.The junction part of the beam thus obtained certainly has a lesser thickness than that obtained by a so-called "swarming" splicing of the previous document, but it is still too large to be able to pass through the calibrated orifice of each of the dies of the continuous manufacturing installation of elongated composite materials described here.

[0006] Document US 4923540 describes a method of joining two rods made of composite materials according to the preamble of claim 1.

[0007] An objective of the invention is to remedy the drawbacks of the aforementioned documents and to provide an original solution for a method and device for splicing multifilament textile fibers for an installation for the continuous production of elongated composite materials.

[0008] This objective is achieved by the invention which proposes a method of splicing the two bundles of multifilament textile fibers in which: an end portion of a first bundle is introduced into a first end of a heat-shrinkable sheath and an end portion of a second bundle is introduced into a second end of the sheath, axially opposite the first, until the ends of the end portions of the two bundles are opposite each other, a hardenable organic material is introduced into the sheath into a space separating said end portions of the bundles so as to join the end portions together by means of a joining portion, the hardenable organic material being introduced into the space existing between the ends of the end portions of the two bundles after the bundles have been placed inside the sheath, a portion of the heat-shrinkable sheath surrounding the joining portion is heated to a predetermined temperature, the hardenable organic material is hardened, and the sheath is removed.

[0009] In other words, the method of the invention makes it possible to join the ends of the two bundles of multifilament fibers end to end in a single piece using a precise dosage of hardenable organic material which forms the binder between the two and this in such a way as to control the shape and dimensions of the joining part obtained after the assembly of the two bundles of fibers. The binder is dosed very precisely in order to obtain a sufficiently strong connection, but without increasing its thickness. According to the invention also, the joining of the two bundles is carried out inside a heat-shrinkable sheath. By heat-shrinkable sheath is understood a flexible tube capable of tightening when heat is applied to it. Thus, when heated, the sheath tightens around the bundles and the binder, holding them firmly in place while the material which binds the bundles hardens.This allows the filaments in the bundles not to mix or change position during assembly and thus to obtain a continuous bundle, in a single piece and of uniform thickness along its length.

[0010] Thus, the method of the invention makes it possible to join two bundles of multifilament textile fibers so as to obtain a common bundle having a junction part of constant thickness, therefore without excess thickness or superposition of the fibers, which allows this single bundle to pass through the different calibration dies of an installation for continuous impregnation of very long fibers with resin for the manufacture of very long elongated composite elements. Furthermore, this method of assembling the end parts of the bundles belonging to two different reels takes little time, of the order of a few minutes, which implies almost continuous operation of the installation, without the need to completely empty the different chambers and compartments thereof, as was the case in the prior art.

[0011] The curable organic material is introduced into the space between the ends of the terminal portions of the two bundles so as to form the joining portion after the bundles have been placed inside the sheath. Thus, introducing the curable organic material into the sheath after the bundles have been placed allows for better positioning thereof relative to the ends of the bundles to be joined. In a preferred embodiment of the invention, the curable organic material is introduced after the bundles have been placed by injection through the sheath, in which case the curable organic material is in a liquid or viscous state before being introduced into the sheath and changes to a solid state after the step of the method in which it is cured.

[0012] The bundles of multifilament textile fibers assembled with the method of the invention may be identical, in particular the fibers are in the same material and have the same linear mass density.

[0013] According to the method of the invention, the ends of the terminal parts of the bundles can be bevelled before they are introduced into the sheath. The two facing bevels are parallel and overlap at least in part, making their assembly using the hardenable material even more robust.

[0014] The end portion of each bundle can be held in position inside the sheath until the curable organic material hardens. This allows for precise positioning of the assembly elements relative to each other throughout the splicing process.

[0015] Said heat-shrinkable sheath may be a polyolefin tube.

[0016] Said sheath may be transparent to UV radiation and preferably it may also be transparent to light.

[0017] The heat-shrinkable tubing can be heated by applying a stream of hot air to a temperature higher than the shrinkage temperature of the tubing. The heat-shrinkable tubing is preferably a polyolefin tube having a pre-established diameter, larger than that of the bundles to be assembled. The hot air heating allows the tubing to shrink quickly and also to cool after the blowing stops. For a polyolefin tubing, such a temperature can be between 210°C and 250°C. Alternatively, an unheated air stream is applied after the tubing is shrunk to accelerate its cooling.

[0018] The heat-shrinkable tubing can be removed by mechanical incision along its length or by heating after initiating an incision at one of its ends. In one variant, the tubing is removed by incision along its entire length. In a preferred variant of the invention, an incision is made at one of the ends of the tubing and then a flow of hot air, heated to the same temperature as that for shrinking the tubing, is applied, which causes the incision to propagate along the length of the tubing and allows its removal.

[0019] The method of the invention may include an additional step of controlling the diameter of the junction of the two bundles. The diameter of the junction portion may be measured to verify that it can pass through the calibrated orifice of the dies. The diameter of the junction portion of the two bundles may then be adjusted if necessary, for example by adjusting the quantity of organic material used.

[0020] By multifilament textile fiber is meant a fiber which comprises several elementary textile filaments arranged side by side to form a bundle, a bundle of which the elementary fibers are unidirectional while being substantially parallel to each other.

[0021] The multifilament textile fibers may be chosen from the group consisting of glass, carbon, silica, basalt, ceramic fibers and mixtures of such fibers, preferably from the group consisting of glass, carbon fibers and mixtures of such fibers and even more preferably said multifilament textile fibers may be glass fibers. These fibers are used to produce elongated composites produced by impregnation of a curable composition of the multifilament textile fibers.

[0022] The curable organic material may be of the thermosetting type, preferably crosslinkable and even more preferably of the vinylester type. By curable organic material is meant a material comprising, by weight, more than 50%, preferably more than 75% and even more preferably more than 90% of curable organic material. Thus, this material may be a thermosetting polymeric material, for example based on unsaturated polyester, polyepoxide, phenolic derivative or aminoplast. Preferably, the curable organic material is crosslinkable. It is for example a resin crosslinkable by ionizing radiation, the final polymerization being able to be triggered and controlled easily by means of an ionizing treatment, for example of the UV or UV-visible type. As crosslinkable curable organic material, a polyester resin (based on unsaturated polyester) or even more preferably a vinylester resin is preferably used.

[0023] Advantageously, the hardenable organic material used for splicing the multifilament textile fibers according to the invention is the same as that used for impregnating these fibers during the manufacture of an elongated composite made by impregnating the multifilament textile fibers with a hardenable composition.

[0024] The object of the invention is also achieved with a device for splicing the two bundles of multifilament textile fibers comprising a support table for means for guiding a first bundle and means for guiding a second bundle arranged in such a way that the end parts of said bundles are movable relative to means for supporting a heat-shrinkable sheath arranged between the means for guiding the first bundle and the means for guiding the second bundle in such a way that the end parts of the bundles can be introduced into the sheath when it is held by said support means, means for introducing a predetermined quantity of hardenable organic material into the sheath, means for hardening said hardenable organic material and means for heating said heat-shrinkable sheath.

[0025] The device according to the invention comprises means for injecting the hardenable organic material through said sheath. This makes it possible to arrange the hardenable organic material at a precise location preferably located between the ends of the two fibers. The sheath can be transparent for even greater precision.

[0026] The device of the invention may comprise means for holding the ends of the bundles in position inside said sheath.

[0027] The device may include means for holding the ends of the sheath in position.

[0028] The device may comprise means for holding the rectilinear part of the sheath in position, in particular to facilitate perforation by a needle for the injection of organic matter.

[0029] Said curable organic material may be a photopolymerizable resin and in that the device may comprise a UV lamp.

[0030] The device of the invention may be part of an installation for the continuous production of elongated composite materials produced by impregnation of a curable composition of multifilament textile fibers comprising a vacuum chamber, an impregnation chamber with a curable resin, means for transporting a bundle of multifilament textile fibers through the impregnation chamber and means for polymerizing the resin.

[0031] The invention will be better understood from the rest of the description, which is based on the following figures: THE figures 1a à 1f are schematic views illustrating the different stages of the method of splicing multifilament textile fibers according to a preferred embodiment of the invention; figure 2 is a sectional view of a support portion of the sheath forming part of a device for implementing the splicing method of the invention; figure 3 is a perspective view of a device for implementing the splicing method of the invention illustrated in the operating position; figure 4 is a perspective view of a device of the device for implementing the method of the invention illustrated at the end of the splicing process.

[0032] In the various figures, identical or similar elements bear the same reference. Their description is therefore not systematically repeated.

[0033] THE figures 1a à 1f schematically illustrate the different stages of the method of splicing the two bundles 1 and 2 of multifilament textile fibers of the invention. In the example illustrated in the figures, the fibers of bundles 1 and 2 are glass fibers of 600 tex each. The method of the invention can be used with glass fibers having linear mass densities which are for example between 60 and 9800 tex. On the figure 1a we note the elements used to carry out the splicing of the invention, in particular two bundles 1 and 2 of multifilament textile fibers and a heat-shrinkable sheath 10. The bundles 1, 2 each have an end part 3, respectively 4 of beveled shape. The heat-shrinkable sheath 10 is a tube of generally cylindrical shape around an axis of revolution or longitudinal axis X-X', tube which has two ends 11, 12 and a generally rectilinear shape. In this example, the sheath has an incision 8 of a few mm made at one of its ends 11.

[0034] There figure 1b illustrates the first step of the method which consists of inserting the ends 3 and 4 of the terminal parts of each bundle 1, 2 into the heat-shrinkable sheath 10. More precisely, the terminal part 3 of the first bundle 1 is introduced into a first end 11 of the heat-shrinkable sheath 10 by sliding it parallel to the longitudinal axis XX' of the sheath 10 and the terminal part 4 of the second bundle 2 into a second end 12, axially opposite the first, by sliding it parallel to the longitudinal axis of said sheath until the ends 3, 4 of the terminal parts of the two bundles 1, 2 are located opposite each other at a predetermined distance forming a space 5 inside the sheath 10.

[0035] The heat-shrinkable sheath 10 is preferably a substantially cylindrical tube with a diameter greater than the diameter of the fiber. The sheath 10 is preferably a tube made of polyolefin and even more preferably it is transparent to light and UV rays. The diameter of the sheath 10 is chosen so that, on the one hand, the bundles of multifilament textile fibers 1 and 2 can slide inside the sheath and, on the other hand, so that, after being subjected to heating, its diameter is smaller than that of the bundles 1, 2 which it encloses. The length of the sheath 10 is also chosen so that it can cover the end parts of the two bundles even after its shrinkage in length after heating. For example, with bundles of 600 tex glass fibers, a heat-shrinkable sheath 10 having an internal diameter of between 1.5 and 2 is used.5 mm, preferably equal to 2 mm, with a wall thickness before shrinkage of between 0.1 and 0.6 mm, preferably equal to 0.25 mm and a length of between 40 and 100 mm, and preferably equal to 60 mm.

[0036] The ends 3, 4 of the beams 1, 2 are cut at an angle so that they can overlap while being spaced and parallel to each other in the space 5 ( fig1b ). Preferably, the ends 3, 4 are held in position during the splicing process.

[0037] In the second step of the process, as seen in the figure 1c , a hardenable organic material is introduced into the heat-shrinkable sheath 10, preferably substantially in the center of the space 5 existing between the facing ends 3, 4 of the terminal parts of the two bundles 1, 2, a space intended to form a junction part 9. The hardenable organic material is, in the example described here, a vinylester resin comprising a photoinitiator. The necessary quantity of resin is introduced into the space 5 inside the sheath 10 using a syringe 20 whose needle 21 passes through the thickness of the sheath 10 exactly at the location intended to receive the resin, the sheath 10 being transparent. In the case of an automated splicing device, the syringe can advantageously be replaced by a small volumetric pump making it possible to inject a precise volume into the sheath 10.In one variant, the sheath is not transparent to light, but it has a marking on its external wall at the location of the space 5. In another variant, the resin is already inside the sheath 10 before the introduction of the terminal parts of the bundles into the sheath. The device may advantageously comprise a removable or non-removable support for the rectilinear part of the sheath in order to facilitate the perforation of the sheath by the end of the needle, and to prevent the sheath from moving under the needle instead of being perforated by it.

[0038] There figure 1d illustrates the third and fourth steps of the method of the invention. The third step consists of shrinking the heat-shrinkable sheath 10. In the example described, a blowing device 30 is used which sends a flow of air heated to a temperature of approximately 210 to 250 °C and which is applied mainly to the part of the sheath 10 surrounding the junction part 9, then moving away from the junction part 9 to distribute the resin on either side of the junction part. The sheath 10 shrinks and thus compresses the resin and the ends 3, 4 of the fibers, which ensures good impregnation of the fibers on a junction part of small diameter. It is observed that the sheath 10 has shrunk over the majority of its length, that corresponding to the area having been heated, except for its ends which have not undergone the application of hot air.In a variant, the hot air flow is applied along the entire length of the sheath 10, starting from one of its ends, 11 (or 12), and heating gradually until reaching the other end 12 (or 11). A device for holding the straight part of the sheath 10 is useful in this step to ensure that the sheath, once thermoformed, is substantially straight and not randomly curved. The sheath 10 is then left to cool in the ambient air or is cooled in an accelerated manner with a flow of cold air. It should also be noted that the small incision made by the perforation of the needle 21 closes on itself as soon as the needle is withdrawn because the material of the heat-shrinkable sheath 10 is flexible, and this incision closed on itself does not lead to a significant leakage of resin before, during and after the thermoforming operation of the sheath 10.

[0039] The fourth step consists of crosslinking the resin using a UV radiation device 40 which is oriented so that the emitted UV radiation is sent into the junction part 9 for a predetermined duration, for example of the order of a few seconds. This has the effect of solidifying the resin and thus making the ends 3 and 4 of the bundles 1 and 2 of fibers integral to form a common bundle or single bundle 50.

[0040] Once the connection of the two beams 1 and 2 has been made, the sheath 10 is removed. In one variant, the sheath 10 is removed by making an incision with a cutting tool along its entire length. In another variant, as illustrated in figure 1e , a notch is initiated either beforehand or during the removal operation using a cutting tool at one of its ends and then a flow of hot air heated to approximately 250°C is applied using the blowing device 30 from the notched area, which allows the notch to propagate along the length of the sheath 10 and to detach into two parts 10a and 10b. If necessary, small pliers can be used to facilitate the removal of the sheath. Still with the aim of facilitating the removal of the sheath, the device for holding the sheath in its rectilinear part can be released during this operation, as will be explained later with reference to the device of the invention.

[0041] The single beam 50 thus obtained by the splicing process of the invention ( fig. 1f ) is ready to be used in an installation for manufacturing elongated composite materials made by impregnation with a curable composition, in particular a photopolymerizable vinylester resin, in particular of the type described in document EP 1 174 250. An operation to check the diameter of the junction part 9 can be carried out, for example, with a calibrated nozzle in two parts before using the single beam 50 in the installation, or using an optical diameter measuring device. This makes it possible to detect any excess thickness (due, for example, to incorrect dosing of the quantity of resin introduced into the space 5) and to avoid breaking the beam thus obtained during its passage through one of the calibrated dies of the installation.

[0042] THE figures 2 , 3 et 4 illustrate different views of an example of a splicing device 100 of the invention. The device 100 comprises a support table 103 for the bundles 1 and 2 to be spliced ​​and for a heat-shrinkable sheath 10. More particularly, the table 103 has the general shape of a rectangular plate and comprises, at one of its ends, means for guiding a first beam 1 produced in the form of a groove 101 extending in the longitudinal direction which is intended to receive the end part of the first beam 1, as well as a device 111 for holding the beam 1 in position. The table 103 also comprises means for guiding a second beam 2 produced in the form of a second groove 102 which is made in the thickness of the table 103 at the opposite end of the groove 101 to receive the end part of the second beam 2 held in position, when present, using a second holding device 112.The holding devices 111 and 112 in the illustrated example are devices of the toggle type. In the central part of the table 103 located between the two grooves 101 and 102 there is a channel 110 which is aligned longitudinally with the grooves 101 and 102 and with the longitudinal axis of the table 103. The channel 110 is intended to receive a heat-shrinkable sheath 10 and forms a means of supporting the latter. The table 103 also comprises at each of its longitudinal ends, a support 104 for a set of guide rollers 106 of the beam 1 and, respectively, a support 105 for a set of guide rollers 107 of the beam 2.

[0043] On either side of the channel 110, at each entry therein, a rigid flared part 119 is arranged, open on the top, to better guide the end 3, respectively 4, of the terminal part of each bundle during its introduction into the sheath 10. More particularly, as seen from above, the part 119 has in its central part a funnel-shaped opening, being wider at its entry end of the bundle 1, 2 and narrowing at the entry of the sheath 10. This makes it easier to introduce the terminal parts of the bundles 1 and 2 into the heat-shrinkable sheath 10, which in this case is a cylindrical tube of constant section over its entire length. In a variant, a cylindrical heat-shrinkable sheath 10 is used, the opposite ends of which are flared in order to allow the introduction of the bundles 1, 2.

[0044] There figure 2 is a cross-sectional view taken through the sheath 10, from the left side thereof, which illustrates how the heat-shrinkable sheath 10 is held in place within the splicing device. The sheath 10 is inserted into the channel 110 having a square-shaped cross-section and dimensions close to the diameter of the sheath so that the sheath is held tight in the channel 110. In order to be able to hold the sheath 10 tight in the channel 110, a sheath support in two parts 113, 114 is used, at least one of which (114) is movable in transverse sliding allowing the opening and closing of the channel 110. More precisely, each part 113, 114 is fixedly mounted on a support part 115, 116, at least one (116) of the support parts being slidably mounted on a rail 118, itself fixedly mounted on the table 103, and able to move away from and approach the other (115) when it is driven in translation.The parts 113, 114 are rigid plates each comprising on the side facing the other, an inclined face 118 opening into the channel 110. The inclined faces 118 facing each other of the parts 113, 114 thus form a gutter at the bottom of which is the channel 110. This ensures good support of the sheath 10 during the splicing operation (. fig. 3 ), as well as being able to easily release the beam obtained with the method of the invention at the end of the splicing operation (see fig. 4 , where part 114 is in the spread position).

[0045] The device 100 also comprises means for introducing a predetermined quantity of hardenable organic material inside the sheath 10, in particular a syringe 20. The syringe 20 is held by a support 122 which is slidably mounted along an inclined rail 123 in order to allow the syringe to be removed at the end of the operation and brought closer to the sheath at the start of the operation. A protective cover 150 of the syringe 20 is held by the support 122 by being mounted with the possibility of rotation around an axis 151 of the support 122. Thus, in operation the cover 150 moves with the syringe 20 along the inclined rail 123 and it is folded down onto the syringe during the injection of the resin and during the withdrawal of the syringe 20. In the case of an automated splicing device, the syringe can be advantageously replaced by a small volumetric pump making it possible to inject a precise volume into the sheath 10.

[0046] The device 100 further comprises means for heating the heat-shrinkable sheath 10, for example a hot air blowing device (not shown) capable of sending a flow of air heated to a temperature between 210°C and 250°C towards the sheath 10. The device also comprises means for curing the resin, such as a UV lamp (not shown), which may be of the Hönle Bluepoint ® type and which is applied to the part of the sheath corresponding to the junction part 9 for a duration of approximately 10 to 15 seconds.

[0047] In operation, a heat-shrinkable sheath 10 is first placed in the channel 110. The end portion of a first bundle 1 of glass fibers is introduced, via the groove 101 and the part 119, into one of the ends of the sheath 10, to a pre-established position, preferably close to the center thereof, and the end portion of the first bundle 1 is fixed in place using the holding device 111. The same thing is done at the other end of the sheath by introducing the end portion of a second bundle 2 of glass fibers which is held in place, after introduction into the sheath 10, using the holding device 112. The parts 113, 114 of the support of the rectilinear part of the sheath 10 are put in position by moving the part 114 in the direction of the part 113 so as to enclose the sheath 10 in channel 110.The syringe 20 is then brought closer to the sheath 10 and, after inserting the needle 21 into the sheath, the syringe plunger is actuated to introduce a predetermined quantity of resin. During this operation, the needle 21 of the syringe is protected by the cover 150.

[0048] The syringe is then withdrawn from the upper part of the rail 123, and the protective cover 150 of the needle is closed over the needle to avoid any risk of injury and to protect the end of the needle from light and UV radiation, and a blowing device is then brought close to the sheath 10 to preferably heat the part of the sheath corresponding to the junction part where the resin has been introduced. The sheath 10 shrinks under the effect of the heat and tightens together the ends of the bundles of glass fibers and the resin. After cooling the sheath, UV radiation is applied to the shrunk part of the sheath to crosslink the resin, which has the effect of obtaining the assembly of the two bundles.

[0049] The sheath 10 is then removed. The single bundle 50 obtained by splicing can be removed by lifting it, after having released the terminal parts of the initial bundles from their holding by the devices 111 and 112. The bundle thus obtained can be passed into the installation, possibly after having checked the value of the diameter of the junction part.

[0050] This produces a spliced ​​composite product that offers mechanical characteristics as high as the areas of the bundle located outside the spliced ​​areas. Thus, the method of the invention makes it possible to produce such a type of composite material without length limit, which can be particularly advantageous for various applications, for example those requiring the splicing of submarine telecommunications cables placed on the ocean floor.

[0051] Other variants and embodiments of the invention may be envisaged within the scope of the invention as claimed. Thus, the splicing device may be independent of the installation, for example portable. The method of the invention may be used with different types of multifilament textile fibers and it is also possible to splice a first fiber with a second having characteristics (for example nature, linear mass density) different from the first.

[0052] Furthermore, it is possible to envisage using the splicing method and device of the invention with a thermally curable organic material, the curing temperature of which is equal to or higher than that applied to shrink the heat-shrinkable sheath. This variant may be particularly advantageous when using non-transparent fibers, such as carbon fibers or basalt fibers which do not allow UV radiation to penetrate into the core.

Claims

1. Method for splicing two bundles (1, 2) of multifilament textile fibres wherein: - an end portion (3) of a first bundle (1) is inserted into a first end (11) of a heat-shrinkable sheath (10) and an end portion (4) of a second bundle (2) is inserted into a second end (12) of said sheath, axially opposite the first end, until the ends of the end portions of the two bundles are facing each other, - a curable organic material is inserted inside the sheath (10) in a space (5) separating said end portions (3, 4) of the bundles (1, 2) so as to join the end portions together by means of a joining portion (9), the curable organic material being inserted into the space (5) existing between the ends of the end portions (3, 4) of the two bundles (1, 2) after the bundles have been placed inside the sheath (10), - a portion of the heat-shrinkable sheath (10) surrounding the joining portion (9) is heated to a predetermined temperature, - the curable organic material is cured, - the sheath (10) is removed.

2. Method according to Claim 1, characterized in that the ends of the end portions (3, 4) of the bundles (1, 2) are bevel-cut before they are inserted into the sheath (10).

3. Method according to one of the preceding claims, characterized in that the end portion (3, 4) of each bundle (1, 2) is held in position until said curable organic material cures.

4. Method according to one of Claims 1 to 3, characterized in that said heat-shrinkable sheath (10) is a polyolefin tube.

5. Method according to one of the preceding claims, characterized in that said heat-shrinkable sheath (10) is heated by applying a stream of hot air at a temperature higher than the shrinking temperature of the sheath.

6. Method according to one of the preceding claims, characterized in that the heat-shrinkable sheath (10) is removed by mechanical incision over the length thereof or by heating after the initiation of an incision (8) at one end (11) thereof.

7. Method according to one of the preceding claims, characterized in that it comprises an additional step of checking the diameter of the joining portion (9) of the two bundles (1, 2).

8. Method according to one of the preceding claims, characterized in that said multifilament textile fibres are selected from the group consisting of glass fibres, carbon fibres, silica fibres, basalt fibres, ceramic fibres, and mixtures of such fibres, preferably from the group consisting of glass fibres, carbon fibres and mixtures of such fibres, and more preferably said multifilament textile fibres are glass fibres.

9. Method according to one of the preceding claims, characterized in that said curable organic material is heat-curable, preferably crosslinkable and more preferably a vinyl ester.

10. Device (100) for splicing two bundles (1, 2) of multifilament textile fibres comprising a table (103) for supporting means for guiding a first bundle (1) and means for guiding a second bundle (2), arranged so that the end portions (3, 4) of said bundles can be moved relative to means for supporting a heat-shrinkable sheath (10) positioned between the means for guiding the first bundle and the means for guiding the second bundle, so that the end portions of the bundles can be inserted into the sheath when it is held by said supporting means, means allowing the insertion of a predetermined quantity of curable organic material inside the sheath, means for curing said curable organic material and means for heating said heat-shrinkable sheath.

11. Device according to Claim 10, characterized in that it comprises means for injecting said curable organic material through said sheath (10).

12. Device according to one of Claims 10 and 11, characterized in that it comprises devices (111, 112) for holding the end portions of the bundles (1, 2) in position inside said sheath (10).

13. Device according to one of Claims 10 to 12, characterized in that said curable organic material is a photopolymerizable resin and in that the device comprises a UV lamp. Facility for continuous manufacturing of elongate composite materials produced by impregnating multifilament textile fibres with a curable composition, comprising a vacuum chamber, a chamber for impregnation with a curable resin, means for conveying a bundle of multifilament textile fibres through the impregnation chamber and means for polymerizing the resin, characterized in that it comprises a splicing device (100) according to one of Claims 11 to 13.